Adjustable steering columns are used to adapt the position of the steering wheel to the seating position of the driver and are known in various embodiments. In many motor vehicles, the vertical slope of the steering column and/or the distance between the steering wheel and the driver can be adjusted. After the steering column has been adjusted, it is fixed in the desired position. For this purpose, a large number of clamping mechanisms for axially and/or vertically adjustable steering columns of motor vehicles are known. Since a high force is required to lock the clamping mechanism, despite the use of lever elements, there is the need for an electrically actuable steering column mechanism.
French Laid-Open Application FR 2 687 628 A1 discloses a clamping mechanism which can be activated by means of an electric actuating element. The steering column is fixed in a particular position selected by the driver by means of the clamping mechanism. A clamping member that can be actuated by the electric actuating element holds the clamping mechanism in a clamping position. When the electric actuating element is activated by the driver, the clamping member is moved from its clamping position into a non-clamping position, with the result that the clamping mechanism is deactivated and the steering column is thus movable relative to the attachment fixed to the vehicle. For example, the driver presses a button, which activates an electric motor to cancel the clamping of the steering wheel. The motor drives the clamping member, which is thereby moved into the non-clamping position.
Also known from the prior art is DE 603 05 795 T2, which discloses electric clamping for a steering column, wherein the clamping device is mounted on the steering column by means of a mounting rod or a mounting hoop. One disadvantage of this solution is the complex construction of the clamping device and the resulting restricted modularity.
Furthermore, DE 699 19 639 T2 discloses an electric clamping mechanism, wherein a movable cam disk is mounted for conjoint rotation on a worm wheel, and a cam disk which is immovable in respect of rotation is fixed on the housing by means of a seating plate. The disadvantage here is the high number of components and the associated costs.
Thus a need exists for an adjustable steering column having an electromechanical fixing device, which has an uncomplicated and compact construction and, at the same time, is inexpensive.